A waterjet and waterjet machining is a tool and process, respectively, using extremely high pressure water (typically between 20,000 and 50,000 psi) forced through a small orifice or “jewel” (typically 0.007″ to 0.015″ diameter) to produce a high velocity concentrated beam of water to cut relatively soft materials. And an abrasive waterjet (hereinafter “abrasivejet”) and abrasivejet machining is a related tool and process, respectively, which uses the same high velocity beam of water to accelerate abrasive particles, such as garnet, to speeds fast enough to cut through much harder materials. Abrasive particles are introduced into the abrasivejet downstream of the jewel when water exiting the jewel creates a vacuum which sucks abrasive particles from the abrasive supply line. The abrasive particles mix with the water in a mixing tube of the abrasivejet before exiting the abrasivejet as a high velocity beam of abrasives.
Various types of pneumatic feed/delivery systems have been used to supply material through a feed line, and in particular feed abrasive particulate material to an abrasivejet. They typically involve a hopper and pneumatic source, such as an air compressor, at an upstream end of the feed system. And the hopper and pneumatic source are connected by a material feed line, such as a hose or pipe, to a second hopper at the abrasivejet. A known problem, however, often seen with this type of feed arrangement is the occurrence of clumping, bridging, and agglomeration of the abrasive particles in the delivery line caused by moisture and condensation from relative humidity. Excessive moisture has been known to develop especially in abrasive materials kept in storage for long periods of time. As a consequence, the bridging and clumping of the material in the delivery line can clog the delivery line until sufficient pressure builds in the line to clear the clog, thereby producing excessive/erratic air pressure and feed rates of the abrasive material to the mixing tube of the abrasivejet. This can disrupt the cutting action in waterjet machining and hamper productivity, as well as reduce edge quality of the machined part.
While various measures have been proposed to dry the abrasive prior to feeding it through the feed line (e.g. by baking-out the moisture using conveyor belts/inline drying system) complex and bulky subsystems are typically required which can significantly increase the cost of abrasivejet machining. Thus a need still exists for a simple efficient, and cost-effective apparatus for preventing clogs in an abrasive feed line by breaking up the clumps of bridged or agglomerated abrasive particles and venting excess air caused thereby, to promote evenflow distribution of material through the feed line. Moreover, it would be beneficial to provide an apparatus which is easily adaptable for use with any commercial delivery line of with little or no modifications.